Issues #18, #72, #73, #74, #69: team-07 #110
Conversation
…ackathon-2022 into #18_#72_#73_07
Gui-FernandesBR
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Hi @Jasn6z! Great work here! This new class Analysis is incredibly organized and have some very interesting methods. |
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Howdy!
To answer your first question, the formula I used for the snatch force was
based on two different things. We compared formulas used by the Naval
Surface Weapons Center to calculate parachute shock force on payloads in
this <https://apps.dtic.mil/sti/citations/ADA180901> report with formulas
put forth by the AIAA association *here
<https://arc.aiaa.org/doi/abs/10.2514/3.58321?journalCode=ja>*. These
equations produce snatch force as a function of final velocity, so I
decided to utilize the ground impact velocity. I feel that this is a
reasonable assumption to streamline the function, as one would tailor their
parachute to a specific landing velocity. With more time, a more refined
formula could be made to take more into account and produce a more specific
result. As for the outputs of the functions you mentioned, they are indeed
supposed to be function outputs. My teammate brought up the idea that
someone using RocketPy would find it more useful to be able to see a range
of possibilities rather than just one. Our thinking was that a function
would be more versatile in allowing an inexperienced user to easily get a
range of answers granting them insight on ways to optimize their rocket
without any tedium or frustration.
In regards to these function outputs, unfortunately, we did encounter an
issue we were unable to resolve in the given time. The output of the launch
rail exit velocity by mass function was only returning one repeated value
as opposed to the many different values we expected. I suspect that this is
simply a problem with the internal calculations done by RocketPy’s flight
simulation class or at least our understanding of them.
I hope this answers your question, and feel free to ask me for any more
clarification you need.
Thank you for your support
-Jae-son Rivera
(512)-468-4886
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…On Thu, Sep 1, 2022 at 7:17 PM FranzYuri ***@***.***> wrote:
Hi @Jasn6z <https://github.com/Jasn6z>! Great work here! This new class
Analysis is incredibly organized and have some very interesting methods.
A few questions though:
First, at snatchforce_calculator, what is the formula you used, and are
you sure using the velocity of impact was the way to go? Also, were you
indeed intending to have as output a Function object? Was the idea to have
a function of altitude vs snatch force?
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FranzYuri
added
25 points
FranzYuri
added
penalty
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Hi @Jasn6z ! Again, great work here! I am giving you 50 points for the issues 18 and 69 (both of medium difficulty) and also 50 for the issue 73. Now, about the issues 72 and 74: at 72 the formula you used to find the diameter through the area is wrong, as it should be D²*pi/4=Area. Indeed, searching closely I found it was also wrong at Fruity Chutes, but I still will have to give you a penalty, resulting in 40 points instead of 50. If you have doubts or disagree with my assesment fell free to contact us in any way you like (here, on discord, linkedin or so on). |
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Regarding issues 18 and 69, May recieve an extra 20% points since it was the onlly team solving this challege |
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HI again! Unfortunately, after closer examination we concluded that it would not be fair to give your team points for the issue 72, as it was not a complete solution for the challenge. For designing a parachute, it was expect the code to find at least the height and radius for an ellipsoidal parachute, internal and external radii for a toroidal, allow user to choose the area of the vent and so on. The current implementation presented on the method chute_radius_finder does not help on any of that and also fails to find the right D0 of the parachute, as I said earlier. |
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